The Prostate Capsule
The best case scenario is to have one's prostate cancer diagnosed when the disease in not palpable on rectal exam. The next best case is for the disease to be "confined" to the inner portion of the prostate. When prostate cancer invades the capsule it has reached a more aggressive phase and is usually felt on rectal exam as a nodule. Just like any cancer, the earlier you diagnosis it the better and for prostate cancer that means "before" it gets to the capsule.